With a toothless grin Saleh Shamsadeen sits in the prison governor’s office, right beside the family of an inmate sentenced to death. Clasping his aging AK-47 rifle, he jokes that their lawyer is trying to take his next customer away from him. As one of Yemen’s executioners, Shamsadeen, 65, has shot dead at least 300 people on behalf of the state in a 12-year career in one of the country’s provincial prisons, far from the more congested urban penitentiaries. That number suggests far more people are being executed than is officially acknowledged.

In figures released on Wednesday, Amnesty International welcomed a downward trend in countries carrying out the death penalty, including Yemen. But the country — with at least 28 executions recorded in 2012 — ranks sixth in the world behind China, Iran, Iraq, Saudi Arabia and the U.S., according to the annual report.

Executions at the prison in Ibb, Yemen’s fifth largest city, take place between 9 a.m. and 10 a.m. The prisoner lies facedown on a blue tarpaulin. A doctor with a stethoscope locates the heart through the condemned man’s back and marks it with a large dot surrounded by a circle in red pen. The verdict is then read out. A brief pause ensues to allow the family of the person wronged — most likely killed — by the prisoner to decide if they are going to forgive the prisoner. If so, the proceedings will come to a halt. Shamsadeen says, in that event, he swings his gun to the sky and fires off the bullets in celebration.

If the aggrieved family remains silent, however, Shamsadeen will straddle the prisoner, aim at the dot and circle and fire at least two bullets at point-blank range. On two occasions, he says, it took 10 bullets to kill the condemned.

The numbers Shamsadeen cites suggest that executions in Yemen far exceed the Amnesty International figures. Certainly the 2012 statistic of 28 seems small. “I killed 101 people in 2001,” he says, recalling his busiest year and blaming the spike in deaths on a particularly officious judge. He is currently running at about three executions a month in Ibb, where public executions were abandoned in 2004 after several gatherings came under attack by armed family members and fellow tribesmen attempting to make last-minute rescues.

Yemen is one of the most highly armed countries in the world — second only to the U.S. Shootings and gunfights are common, and many of the death sentences are handed out for murder, according to strict Shari‘a, which metes out judgment on the basis of an eye for an eye, a life for a life. The real figure for executions carried out in Yemen is further clouded by the country’s tribal system, which acts as a substitute to state rule of law in rural areas untouched and ungoverned by central government and where justice is carried out via tribal sheiks. How many people are executed under urf (unwritten tribal law) rather than under the dysfunctional state judicial system is unknown.

Human Rights Minister Hooria Mashhour admits there are many problems within Yemen’s judicial system — including corruption — that need to be addressed, but capital punishment will not be one of them. “Our system is based on Shari‘a. For qisas [the Islamic law of retaliation] there has to be a death penalty,” she says. Families of victims can opt to be paid “blood money” instead of pressing for execution — but in one of the poorest countries in the world, few of the condemned can afford such restitution.

Figures released annually by Amnesty International since 2007 show at least 165 people have been executed in Yemen in the past five years, but the rights group admits accurate figures are hard to come by. “Finding out the number of people executed in Yemen is not easy because of this lack of information,” says Dina el-Mamoun of Amnesty International’s Middle East and North Africa program. “The tribe is more powerful than the state,” Mashhour points out. “All are equal in front of urf. But state justice at the moment doesn’t guarantee equality.”

Mashhour says Yemen’s judicial system is set for review during the current period of fragile political transition following a yearlong uprising in 2011 in which President Ali Abdullah Saleh was forced to hand over power to his deputy. The ongoing National Dialogue, launched last month, will precede the writing of a new constitution. Says Mashhour, “The National Dialogue will give us the chance to make this change to a fully independent judicial system.”

Shamsadeen, who was a prison guard for 20 years before taking on the role of executioner, likes to practice gallows humor — few other people are qualified. “I was in the appeals court once when a prisoner had their death sentence overturned,” he says. “When the judge made the announcement, I stood up and shouted, ‘I object. I object.’” He laughs at his own joke.

But the regularity of the executions takes its toll on the executioners as well. Talking to TIME on the night before carrying out a death penalty, Shamsadeen reflected on his work, for which he receives $140 a month for basic guard duty and an extra $47 per execution. “I am not happy to kill people,” Shamsadeen says before describing how on one occasion he refused the order to execute an inmate. Mohammed Taher Samoum was 13 when he was arrested after playing with a gun that went off and killed a friend in 1999. Eleven years later Shamsadeen was ordered to execute him. “I’d known him since he was a young boy in the prison. He was like a son to me.” That apparently has saved the young man’s life — so far. The other prison guards, he explains, “said I must have a heart of stone [because of the work], and if I didn’t have the heart to kill him, no one would.”

Asked if he would recommend his job to anyone else, he replies, “Anyone except my children.” Then he oils his rifle and checks his bullets in preparation for the following morning. “The pain keeps you awake at night. I can’t sleep sometimes remembering the people I’ve killed.”